The invention relates to an improved typist's copy holder having a motor driven line guide. Copy holders include a face plate which provides a supporting surface for the copy matter, or document to be copied; a brace support member to hold the face plate in an appropriate inclined position; and a line guide adapted to extend transversely across the copy matter. In the typical manual copy holder, the line guide is magnetically mounted on the face plate and is manually advanced, or slided downwardly, a line at a time, by the typist. However, moving the line guide manually is time consuming, as it requires the typist to remove at least one hand from the typewriter keys.
To increase typing efficiency, copy holders have been designed having motor driven line guides actuated by either a foot switch or by the typewriter carriage return. U.S. Pat. No. 4,195,429 describes a copy holder with a motor driven line guide. The apparatus includes a flat, flexible, metal drive belt. The line guide is magnetically attached to the drive belt. The magnetic attachment drivingly connects the belt and line guide, and maintains proper alignment of the line guide. However, it is undesirable to have magnets near some common office electronic equipment.
A design problem with electrically driven line guides has been assuring that the line guide moves the appropriate distance each time the motor is activated. Mechanical control means, such as cam operated microswitches, have been employed to deactivate the motor when the line guide moves the required distance. In other designs, it has simply been left to the typist to control the distance which the line guide advances by maintaining the foot switch closed for the necessary time interval. There is obviously a need for a simple, reliable copy holder in which the line guide is automatically advanced a preselected distance upon operation of control means.